Non-woven fabric sheet

Abstract

A sheet of nonwoven fabric for use in absorbent articles such as disposal diapers, sanitary napkins, wipes, etc., the sheet of nonwoven fabric being suitable for holding high-viscosity excreta such as soft feces. The sheet of nonwoven fabric has, formed in a first surface thereof, a plurality of ridges and grooves which extend in the machine direction. The sheet comprises a first fibrous layer and a second fibrous layer, the first fibrous layer being located on the first-surface side and the second fibrous layer being located on the second-surface side, which is on the reverse side from the first surface. The second fibrous layer comprises fibers having the ability to be crimped, and the first fibrous layer comprises heat-fusible fibers which are not crimped at the crimping initiation temperature of the fibers having the ability to be crimped. In a plan view from the first-surface side, the peripheries of the ridges have a shape which is composed of repeated meanders.

1 . A non-woven fabric sheet in which a plurality of ridges and grooves are formed on a first surface thereof extending in a machine direction, wherein the non-woven fabric sheet comprises a first fibrous layer on a first surface side and a second fibrous layer on a second surface side opposite from the first surface side, the second fibrous layer comprises latent crimpable fibers, the first fibrous layer comprises heat-fusible fibers that do not demonstrate crimping at the crimping starting temperature of the latent crimpable fibers, and when the non woven fabric sheet is viewed from overhead from the first surface side, the outer edges of the ridges have a repeated meandering shape. 
     
     
         2 . The non-woven fabric sheet according to  claim 1 , wherein, sites where the height of the ridges is relatively high over the direction in which the ridges extend and sites where it is relatively low are formed in the ridges. 
     
     
         3 . The non-woven fabric sheet according to  claim 1 , wherein the ridges have an enhanced three-dimensional random orientation as a result of at least a portion of the fibers therein generating curvature or bending. 
     
     
         4 . A process for producing a non-woven fabric sheet, comprising:
 a) a step for opening a fiber assembly containing latent crimpable fibers by passing through a carding machine to form a web containing latent crimpable fibers,   b) a step for opening a fiber assembly containing heat-fusible fibers that do not demonstrate crimping at the crimping starting temperature of the latent crimpable fibers by passing through a carding machine to form a web containing heat-fusible fibers,   c) a step for superimposing the web containing latent crimpable fibers and the web containing heat-fusible fibers to form a laminated web,   d) a step for realigning the fibers so that ridges and grooves are formed in the laminated web, and portions in which the degree of fiber entanglement in the direction in which the ridges are continuous is relatively high and portions in which it is relatively low are alternately formed,   f) a step for heating the web in which fibers have been realigned to cause the latent crimpable fibers to demonstrate crimping, and   g) a step for heating the web in which crimping has been demonstrated by the latent crimpable fibers to fuse the heat-fusible fibers at sites where they mutually intersect.   
     
     
         5 . The process according to  claim 4 , wherein step d is a step in which the laminated web is transported by placing on a support, in which liquid passage portions and liquid blocking portions extending in parallel in a cross-machine direction are arranged by alternately repeating in a machine direction, while forming a plurality of ridges and grooves extending in parallel in the machine direction by spraying a liquid from a plurality of nozzles arranged in a row in the cross-machine direction onto the surface of the web side of the laminated web that contains the heat-fusible fibers. 
     
     
         6 . The process according to  claim 4 , wherein step f is a step in which the web is heated to a temperature at which the latent crimpable fibers demonstrate crimping and which is lower than the fusing temperature of the heat-fusible fibers. 
     
     
         7 . The process according to  claim 4 , wherein step f is carried out in a state in which there is little resistance to force that attempts to shrink the latent crimpable fibers in the machine direction as a result of crimping. 
     
     
         8 . The process according to  claim 7 , wherein the transport speed of step f is slower than that of the previous step. 
     
     
         9 . The process according to  claim 7 , wherein a floating dryer is used in step f. 
     
     
         10 . The process according to  claim 4 , comprising
 e) a step for transporting the laminated web obtained in step d to step f between step d and step f.   
     
     
         11 . The process according to  claim 4 , comprising
 h) a step for cooling the web obtained in step g after step g.   
     
     
         12 . An absorbent article containing the non-woven fabric sheet according to  claim 1 .